do birds have small brains

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SignificanceBirds are remarkably intelligent, although their brains are small. Corvids and some parrots are capable of cognitive feats comparable to those of great apes. How do birds achieve impressive cognitive prowess with walnut-sized brains? We investigated the cellular composition of the brains of 28 avian species, uncovering a straightforward solution to the puzzle: brains of songbirds and parrots contain very large numbers of neurons, at neuronal densities considerably exceeding those found in mammals. Because these “extra” neurons are predominantly located in the forebrain, large parrots and corvids have the same or greater forebrain neuron counts as monkeys with much larger brains. Avian brains thus have the potential to provide much higher “cognitive power” per unit mass than do mammalian brains.

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Phylogenetic relationships among the 28 species examined. The tree was constructed using.

Brain dissection and labeling of neurons and nonneuronal cells. (

Total Numbers of Neurons.We found that the bird brains have more neurons than mammalian brains and even primate brains of similar mass (

Comparing the cellular scaling rules of parrots and songbirds’ brains to those of mammals (.

Cellular densities in avian brains. (

In mammals and birds, the relative distribution and densities of neurons (.

The size, structure, and quantity of neurons in the avian species under investigation Representative brains’ dorsal and lateral views are accompanied by data on the mass (red), total number of brain neurons (yellow), and number of pallial neurons (blue). M, million. (Scale bar, 10 mm. )Table S1. Cellular composition of the brains of 28 bird species.

Species ordered by increasing brain size. All values are given as mean ± SD;

Species n Body mass, g Brain mass, g Total neurons, ×106 Total nonneurons, ×106
Parrots
Green-rumped parrotlet 3 23.2 ± 0.7 1.146 ± 0.042 227.20 ± 3.81 135.00 ± 4.70
Budgerigar 3 35.3 ± 4.6 1.317 ± 0.041 321.82 ± 10.62 176.05 ± 4.26
Cockatiel 3 101.0 ± 4.6 2.205 ± 0.132 452.77 ± 44.51 234.66 ± 10.25
Eastern rosella 3 102.0 ± 3.4 2.716 ± 0.032 641.88 ± 79.00 318.17 ± 47.28
Monk parakeet 3 94.0 ± 1.7 3.420 ± 0.168 696.77 ± 75.26 393.49 ± 21.06
Alexandrine parakeet 3 223.0 ± 5.3 5.699 ± 0.492 1,096.26 ± 89.81 572.74 ± 28.11
Goffins cockatoo 2 244.8 ± 3.5 8.275 ± 0.548 1,160.59 ± 101.87 792.22 ± 39.88
Gray parrot 2 453.5 ± 47.4 8.827 ± 0.859 1,565.93 ± 128.99 880.59 ± 2.06
Sulfur-crested cockatoo 1 430.0 10.131 2,121.93 1,001.81
Kea 1 708.0 13.593 2,148.67 975.57
Blue and yellow macaw 1 1,008.0 20.731 3,135.79 1,800.03
Variation, max./min. 43.3× 18.1× 13.8× 13.3×
Songbirds
Goldcrest 3 4.5 ± 0.1 0.357 ± 0.022 163.87 ± 8.67 44.16 ± 6.57
Zebra finch 3 17.4 ± 2.1 0.494 ± 0.040 135.98 ± 6.82 59.75 ± 2.03
Blackcap 3 16.6 ± 1.3 0.774 ± 0.037 156.73 ± 18.91 86.28 ± 9.18
Great tit 3 17.1 ± 0.3 0.940 ± 0.066 225.98 ± 46.97 115.43 ± 23.43
Starling 3 73.1 ± 1.9 1.855 ± 0.047 482.50 ± 88.29 215.64 ± 13.49
Blackbird 3 85.0 ± 7.5 1.887 ± 0.117 379.41 ± 43.33 222.57 ± 27.48
Azure-winged magpie 2 84.1 ± 16.0 3.393 ± 0.486 740.59 ± 0.35 349.49 ± 33.17
Hill mynah 2 262.1 ± 30.7 3.670 ± 0.362 906.13 ± 45.38 380.79 ± 3.56
Eurasian jay 3 160.0 ± 12.5 4.597 ± 0.307 1,085.42 ± 159.56 484.42 ± 32.87
Magpie 3 178.6 ± 11.5 5.425 ± 0.617 897.27 ± 57.43 535.97 ± 15.96
Jackdaw 3 209.7 ± 25.1 6.023 ± 0.305 967.99 ± 106.66 565.92 ± 37.87
Rook 3 429.3 ± 35.6 8.357 ± 0.312 1,508.72 ± 38.25 855.55 ± 92.10
Raven 3 1,070.7 ± 73.2 14.135 ± 0.558 2,170.68 ± 72.67 1,242.85 ± 98.19
Variation, max./min. 237.9× 39.6× 16× 28.1×
Other birds
Rock pigeon 3 322.5 ± 22.7 2.095 ± 0.123 309.96 ± 33.33 262.18 ± 18.94
Red junglefowl 3 861.3 ± 107.3 2.819 ± 0.200 220.84 ± 44.50 286.68 ± 17.35
Barn owl 3 369.7 ± 37.7 5.618 ± 0.404 689.54 ± 39.64 522.49 ± 25.29
Emu 2 32,600.0 ± 1,414.2 21.811 ± 2.037 1,335.40 ± 29.01 1,528.66 ± 118.97

Power laws were calculated from the average species values listed in

Dependent variable Independent variable Power law r2 P value (exponent) 95% confidence interval
Parrots
MBR NBR MBR = 2.669 × 10−10 × NBR1.144 0.979 <0.000 1 1.020–1.269
MTEL NTEL MTEL = 1.356 × 10−9 × NTEL1.075 0.967 <0.000 1 0.928–1.221
MDIE NDIE MDIE = 5.027 × 10−15 × NDIE2.031 0.827 <0.000 1 1.395–2.668
MTEC NTEC MTEC = 5.492 × 10−16 × NTEC1.998 0.945 <0.000 1 1.645–2.350
MCB NCB MCB = 3.030 × 10−11 × NCB1.198 0.974 <0.000 1 1.052–1.344
MBS NBS MBS = 1.752 × 10−20 × NBS2.968 0.911 <0.000 1 2.304–3.633
MBR OBR MBR = 3.267 × 10−10 × OBR1.170 0.989 <0.000 1 1.076–1.263
MTEL OTEL MTEL = 9.805 × 10−10 × OTEL1.126 0.991 <0.000 1 1.043–1.208
MDIE ODIE MDIE = 2.622 × 10−17 × ODIE1.102 0.989 <0.000 1 1.015–1.189
MTEC OTEC MTEC = 3.822 × 10−10 × OTEC1.160 0.938 <0.000 1 0.943–1.380
MCB OCB MCB = 2.440 × 10−10 × OCB1.160 0.970 <0.000 1 1.031–1.343
MBS OBS MBS = 2.567 × 10−10 × OBS1.186 0.987 <0.000 1 1.081–1.288
Songbirds
MBR NBR MBR = 4.699 × 10−11 × NBR1.227 0.962 <0.000 1 1.068–1.387
MTEL NTEL MTEL = 4.678 × 10−11 × NTEL1.134 0.940 <0.000 1 0.949–1.320
MDIE NDIE MDIE = 2.322 × 10−16 × NDIE2.208 0.952 <0.000 1 1.882–2.520
MTEC NTEC MTEC = 2.024 × 10−14 ×NTEC1.736 0.934 <0.000 1 1.440–2.033
MCB NCB MCB = 2.013 × 10−11 × NCB1.206 0.972 <0.000 1 1.072–1.340
MBS NBS MBS = 2.776 × 10−17 × NBS2.445 0.950 <0.000 1 2.081–2.810
MBR OBR MBR = 1.536 × 10−9 × OBR1.093 0.998 <0.000 1 1.060–1.125
MTEL OTEL MTEL = 5.399 × 10−9 ×OTEL1.043 0.997 <0.000 1 1.007–1.080
MDIE ODIE MDIE = 6.292 × 10−9 × ODIE0.992 0.996 <0.000 1 0.953–1.032
MTEC OTEC MTEC = 1.465 × 10−9 × OTEC0.946 0.994 <0.000 1 0.897–0.996
MCB OCB MCB = 2.102 × 10−10 × OCB1.191 0.965 <0.000 1 1.043–1.339
MBS OBS MBS = 2.907 × 10−9 × OBS1.040 0.993 <0.000 1 0.980–1.100

Brain–body scaling in birds and mammals. (

Quantitative information currently accessible for the mammalian and avian species that the isotropic fractionator was used to examine (.

FAQ

Do birds have tiny brains?

Although bird brains are tiny, they’re packed with neurons, especially in areas responsible for higher level thinking.

How big is a bird’s brain?

In birds, brain sizes range from 0.22 g in hummingbirds, over 2 g in pigeons, to 14 g in Keas and ravens and 27 g in ostriches (Rehkämper et al., 1991b; Peng et al., 2010; Olkowicz et al., 2016).

Which bird has highest IQ?

Neuroscientists from the university of Alberta have identified parrots as the most intelligent bird. A few years ago, scientists from Charles University in Prague had found that birds have higher intellect when compared with animals and mammals.

How intelligent are small birds?

Despite the small size of their noggins, parrots and corvids show remarkable intelligence, solving some puzzles as well as primates. Previous studies have shown the brains of songbirds and parrots contain very large numbers of neurons in their forebrains, sometimes even more than monkeys.